After the return of the dark lord it was clear that he will kill harry. So harry and his frends decided to fight against him. They started to make a team and practise defence magical spells. Voldemort started to play with the mind of harry.
He started torchering people so that harry makes a mistake. He targeted serious black and when harry came to save him he along with his frends got trapped in the plan of dark lord. But dumbledoor apeared and had a serious fight with voldemort and saved everybodies like exept serious black. He was killed by his own cousin sister.